Plastic compositions comprising biphenylyl esters of aliphatic acids



Patented Sept. 30, 1952 PLASTIC COMPOSITIONS COMPRISING BI- PHENYLYL ESTERS F ALIPHATIC ACIDS Carl B. Havens, Hope, Mich, assignor to The Dow Chemical Company, Midland, Mich., a corporation'of Delaware Serial No. 217,689

- NQ Drawing. Application March 2 1951,

8 Claims." (01. 260 45.85)

This invention relates to new plastic compositions containing biphenylyl esters of aliphatic acids pf from 10, to 18 carbon atoms. The invention relates in particularto new compositions of matter comprising one or more such esters as phatijc acids of from to 18 carbon-atoms" or a stabilizing plasticizers in polymeric bodies conmixture of two or more of these esters, which taining vinyl chloride insubstantial amount. will afford improved protection against the in- The polymers of vinyl chloride; and many. of jurious eifectsof heat and light. I the copolymers and plasticized compositions The biphenylyl esters of I unsubstituted thereof, are now well-known in the art. Most 10 straight-chain aliphatic monocarboxylic -facids of these polymers,copolymers, and compositions containing from 10 to 18 carbon -atoms per can be molded or extruded to form useful, shaped molecule have been prepared, "and the} stated articles. They commonly suffer from the disobjects may now be attained 'throughthe-"inadvantage of undergoing decomposition when excorporation of said esters in polymeric composed for prolonged periodsto the effects of light. positions containing vinyl chloride insubstan- Furthermore, it has been found that'such prodtial amount. The most effective esters of this ucts tend to darken after prolonged exposure to class appear to be the biphenylyl esters Pofcapelevated temperatures. This darkening is acric, lauric, palmitic, stearic, oleic, and linoleic companied by a change in othe'r physical 'propacids. Among the other esters which may "be erties of the polymeric product and is assumed employed for the present purpose are the bito be evidence of partial decomposition. phenylyl esters of the following acids: undec- The plastic properties of the above-mentioned anoic, tridecanoic, tetradecanoic (myristic), polymers and copolymers'may be modified conp'entadecanoic, heptadecanoic, the 2-, 3-, 4- siderably by, adding certainfplasticizing agents 1 and Q-decenoic acids, the 9- and IO-un'decenoic either to the polymeric material or to the monoacids, the 2-, 4-, 5-, 9-, and ll-dodecen'oic acids, mer or mixture of monomers from which it is the 2- and 12- tridecenoic acids, the 4-, 5-, and prepared. Most of the plasticizers are appar- Q-tetradecenoic acids, the 2- and 14-penta'decently incapable of preventing or Of substantially enoic acids, the 2-, 7-, and 9-hexadecenoic reducing the tendency of these polymers to deacids, 2-heptadecenoic acid, the 2-, 3-, 4-,;55 compose or to darken when exposed for pro- 6-, 7-, 8-, 10-, '11-, and lz-octadecenoic' acids, longed periods to the effects of light or heat. elaidic' acid, 2,4-pentadienoic acid, 2,4-h'exadi- These undesirable efiects' ar'e particularly noticeenoic acid (sorbic acid), the geometrical isomers able when dealing with) articles having a thin of linoleic acid, 9,11-octadecadienoic acid, linosection, such as is found in films or filaments. lenic acid, eleostearic acid, hiragonic acid,'mo- Some addition agents have been found to stabilize roctic acid, and stearidonic acid. 7 I the polymer and copolymer somewhat against Mixtures of the above-named esters may be the effects of heat or light. In'a few instances employed effectively as stabilizingfmodifiers in the stabilizing agent has, 'aswelLsome plasticizthe compositions of the present invention. Vegeing properties. While various protective agents table and animal oils contain the glycerides of have beenproposed, one is still'desired which'has various aliphatic acids of from 10 to iii-carbon good plasticizing properties and provides ade- 40 atoms. The acidsobtained from such oils may quate. stabilization against the efiects-of both be: esterified with a phenyl phenol toyield the heat and light. corresponding biphenylyl esters which are mostv It is accordingly among the objects" of'the satisfactory as stabilizing modifiers in the cornpresent invention to provide a vinyl chloride positions of the present invention. Among-the polymer composition which is stable both to various commercial oil fatty acids which may be ultra-violet light from artificial sources'and' that esterified with phenyl phenol and employed'for contained in direct sunlight, so that the comthepresent purpose are coconut oil fatty acid, position may be stabletoward any common type hydrogenated animal oil fatty acids, palm oil of light to which'it may be subjected. .A fu'rfatty acid, animal-oil fatty acidgcottonseed oil ther object is to provide a stabilized composition fatty. acid, soyabean oil fatty acid, peanut oil as aforesaid which can be heated to temperatures sufficiently above the softening point of the composition so that the polymer may be readily worked while in a plastic state, .without decomposition. A still further object is to provide a heat and light stabilizerin the form of a'plasticizer for polyvinyl chloride compositions. A related object is to provide such a composition containing a biphenylyl esteryof certain alifatty acid, tall oil fatty acids, sunflowerseed oil and linseed oil fatty-acid. Someof the oils from which these oil fatty acids may-be 'obtainedare listed in the table Constants of Vegetable and Animal Oils, Fats and Waxes. pages 1318-1319 operations.

is subsequently heated to a temperature of about 85 0., preferably under vacuum, thus removing the residual trace of phosphorus trichloride. The crude acid chloride is added slowly to an equi- -molar amount of phenyl phenol maintained at about 60 C. and under a partial pressure of l 20 millimeters of mercury (absolute) during the course of about one hour. At the end of this period, the reaction mixture is heatedto 125 C.

at the same reduced pressure thus completing the esterification. The crude ester product-may be Washed with a dilute sodium carbonate solution until it, exhibits a neutral reaction, and .finally with water, to remove traces of inorganic salts. The product is thenpurified by distillation under reduced pressure I Esters so prepared have been found useful in stabilizing and plasticizing polyvinyl chloride compositions for fabrication into films, filaments,

andother articles by hot extrusion or molding They are especially useful in the preparation of odorless, heat and light stable plastic articles.

The amount of the ester to be employed may vary with the typeof polymer or copolymer to which it is added and with the conditions against which it is desired to protect the polymeric product. Amounts varying from about per cent by weight up to and including 50 per cent, or other plasticizing quantities of the ester modifier, are

employed. Larger amounts than those indicated 1 may, of course, be employed especially when said ester is relied upon to provide an unusually large amount of plasticity. Amounts smaller than 5 per cent may be sufficient in products which require little plasticity and which will-not be subject to serious exposure to light or'heat. The preferred and most practical amounts of these esters for the protection and modification of these polymers are from 15 to 35-per cent.

Among the polymers or copolymers which have been treated advantageously with the biphenylyl esters of the previously-defined aliphatic acids in accordance with the present invention are polyvinyl chloride and copolymers comprising at least 50 per cent vinyl'chloride with lesser proportions of vinylidene chloride, vinyl acetate, and acrylonitrile, or variousrmixtures thereof,

The heat and light stabilizing esters of the present compositions maybe incorporated with the polymer or copolymer by any of several methods, e.-g. by grinding .the materials in a ball mill or byicompounding them on hot rolls in a manner similar to compounding rubber compositions.

Regardless of the means whereby the stabilizing modifiers are incorporated-with polymers or i copolymers, a, marked stabilizingefiect is exhibited when the mixture is exposed to heat or light. Thus a film or filament prepared from polymeric vinyl chloride, or a copolymer of vinyl chloride and vinylidene chloride which does not contain a stabilizing agent, may assume a dark brown or black coloration after several days exposure 4 to sunlight or after about one-half hour exposure to a temperature of C. In contrast, analogous articles comprising preferred amounts of the biphenylyl esters may be exposed to sunlight or to more concentrated ultra-violet rays for long periods or to a temperature of 150 C. for several hours without becoming materially discolored.

The following examples illustrate the practice of the invention:

Example 1 Two parts by weightof a commercial grade of polyvinyl chloride in powder form, was compounded with 1 part of one of the biphenylyl esters. For comparison, a blank was similarly compounded from polyvinyl chloride in admixture with tricresyl phosphate, a commonly employed commercial plasticizer, in the same proportions as the new compositions. compositions were heated in an oven at 70 C. for 2 hours. All compositions were then heated at 150 C. for various lengths of time, after being compression-molded for 1 minute at C. into samples of uniform'thickness (0.025 inch). The amount of decomposition was judged from the darkening of the various samples. The amount of time required for each sample to attain a dark brown or black coloration was used as an index to the'rate of decomposition. Thus, a modifier was rated as being a poor heat stabilizer if its plastic composition turned to a dark brown or black coloration within the first hour of the heat treatment. Aheat exposure'of 1 hour resulted in a dark brown coloration of the blank sample. The three samples comprising Z-biphenylyl oleate, Z-biphenylyl linoleate, and the lauric acid ester of a commercial mixture of 3- and 4- phenylphenols required 4 hours to form the same dark brown color, showing a thermal stability of four times that of the blank. The four samples comprising 2'-biphenylyl caprate, 2-biphenyly1 laurate, 2-biphenylyl palmitate, and Z-biphenylyl stearate did not decompose suificiently to attain the standard dark'brown color in more than 8 hours of exposure to the same heat treatment, showing a heat stability of over eight times that of the blank sample.

Example 2 Identical samplemoldings of the ester modifiers and the blank were prepared as in Example 1. All samples were exposed to ultra-violet rays for 320 hours in a standard fadeometer at a temperature of about 35 to 40 C. and a relative humidity of about 50 per cent. In all determinations, observations were made on test samples before, during and after exposure, the color change or darkening indicating the degree of deterioration resulting from the treatment. As in Example 1,'the effectiveness of each modifier, as a light stabilizer, was evaluated according to the length of time that its plastic composition resisted the formation of the same pre-established standard dark brown coloration.

A light exposure of 80 hours resulted in a dark brown coloration of the blank sample. In contrast to this, the 7- samples comprising 2-biphenylyl caprate, Z-biphenylyl laurate, 2-biphenylyl palmitate,., Z-biphenylyl stearate, 2-biphenylyl oleate, Z-biphenylyl linoleate and the lauric acid ester of a commercial mixture of 3- and 4-phenylphenols .did not deteriorate sufficiently to attain the same dark brown color in more than 320 hours exposure to the same light treatment, showing a light stability of over 4 All of these times that of the blank sample. f the modifiers tested, Z-biphenylyl linoleate exhibited an exceptional and outstanding light stabilizing effect in polyvinyl chloride compositions, when tested as described above.

Example 3 Sample moldings of 2-diphenylyl esters of various commercially-obtained animal and vegetable oil fatty acids were prepared and tested for heat and light stability in the same manner as the samples of Examples 1 and 2. The blanks employed were of the same composition as those used in the previous examples. Those samples containing the Z-biphenylyl esters of coconut oil fatty acid, palm oil fatty acid, soyabean oil fatty acid, vegetable oil fatty acid, and linseed oil fatty acid, required a 2-hour heat exposure to form the same characteristic dark brown color, and were seen to have a thermal stability twice that of the blank. In light exposure tests, other samples of polyvinyl chloride compositions each containing one of the 2-biphenyl esters of coconut oil fatty acid, palm oil fatty acid, animal oil fatty acid, cottonseed oil fatty acid, vegetable oil fatty acid, tall oil fatty acid, and linseed oil fatty acid did not deteriorate sufliciently to attain the same dark brown color in more than 320 hours of light exposurea, time improvement in light stability of over 4 times that of the blank sample. Of the modifiers tested, the Z-biphenylyl esters of cotton seed oil fatty acid, soyabean oil fatty acid and vegetable oil fatty acid exhibited an exceptional and outstanding light stabilizing effect in polyvinyl chloride compositions.

Other tests have indicated that improved stability is obtained in a polyvinyl chloride composition when the amount of the ester modifier is as little as 5 per cent by weight. Usually it is unnecessary to employ more than 35 per cent by weight of these compounds for their stabilizing and plasticizing effect, and in most cases, to 35 per cent is suflicient for the purpose.

The invention is not limited to the use of the particular polymer of the examples but is applicable generally to all polymeric vinyl chloride compositions, comprising at least 50 per cent polyvinyl chloride, which tend to darken 6 when heated or when exposed to ultra-violet radiation, prolonging in each case the useful life of the polymer under exposure to heat or light.

This application is a continuation-in-part of my copending application Serial No. 194,187, filed November 4, 1950 and now abandoned.

I claim:

1. A composition of matter comprising a polymeric product containin at least 50 per cent of vinyl chloride in the polymer molecule, and, as a stabilizing agent therefor, from 5 per cent by weight up to and including plasticizing quantities, of the biphenylyl ester of at least one unsubstituted straight-chain aliphatic monocarboxylic acid containing from 10 to 18 carbon atoms and selected from the class consisting of the alkanoic acids and the alkenoic acids containing from 1 to 4 ethylenic double bonds.

2. The composition as claimed in claim 1 wherein the polymeric product is polyvinyl chloride.

3. The composition as claimed in claim 1 wherein from 15 to per cent of said stabilizing agent is employed.

4. The composition as claimed in claim wherein the polymeric product is polyvinyl chlo-.

5. The composition as claimed in Claim 3 wherein the polymeric product is polyvinyl chloride and the stabilizing agent consists essentially of Z-biphenylyl caprate.

. 6. The composition as claimed in claim 3 wherein the polymeric product is polyvinyl chloride and the stabilizing agent consists essentially of 2-biphenylyl palmitate.

7 The composition as claimed in claim 3 wherein the polymeric product is polyvinyl chloride and the stabilizing agent consists essentially of 2-biphenylyl oleate.

8. The composition as claimed in claim 3 wherein the polymeric product is polyvinyl chloride and the stabilizing agent consists essentially of 2-biphenylyl linoleate.

' .CARL B. HAVENS.

No references cited. 

1. A COMPOSITION OF MATTER COMPRISING A POLYMERIC PRODUCT CONTAINING AT LEAST 50 PER CENT OF VINYL CHLORIDE IN THE POLYMER MOLECULE, AND, AS A STABILIZING AGENT THEREOF, FROM 5 PER CENT BY WEIGHT UP TO AND INCLUDING PLASTICIZING QUANTITIES, OF THE BIPHENYLYL ESTER OF AT LEAST ONE UNSUBSTITUTED STRAIGHT-CHAIN ALIPHATIC MONOCARBOXYLIC ACID CONTAINING FROM 10 TO 18 CARBON ATOMS AND SELECTED FROM THE CLASS CONSISTING OF THE ALKANOIC ACIDS AND THE ALKENOIC ACIDS CONTAINING FROM 1 TO 4 ETHYLENIC DOUBLE BONDS. 